Control apparatus

ABSTRACT

A velocity decay actuated self-destruct mechanism for use with stabilized projectiles. Dynamic pressure against a nose cap due to movement of the projectile through a fluid medium is balanced by spring pressure from within the ogive of the projectile. Movement of the nosepiece as the spring pressure overcomes the dynamic pressure causes self-destruct of the projectile.

United States Patent 1151 3,636,880 Aske 1451 Jan. 25, 1972 [541 CONTROLAPPARATUS 2,651,993 9/1953 Berzof et al ..102/s0 3,326,132 6/1967 Tlam..l02/80 [72] Inventor: Robert L. Aske, Minneapolis, Minn. [73]Assignee: Honeywell Inc., Minneapolis, Minn. Primary Emmi"er BenjaminBorcheh Assistant Examiner-Thomas H. Webb Flledi 1963 Attorney-CharlesJ. Ungemach, Ronald T. Reiling and Albin 21 Appl. No.: 783,581 Medved[57] ABSTRACT 5 U. l. 7 8 g fl 3 F42c 15/04 F426 A velocity decayactuated self-destruct mechanism for use [58] Field 102/71 80 withstabilized projectiles. Dynamic pressure against a nose p due tomovement oflhe projectile through a fluid medium [56] References Citedis balanced by spring pressure from within the ogive of the projectile.Movement of the nosepiece as the spring pressure UNITED STATES PATENTSovercomes the dynamic pressure causes self-destruct of the ro'ectile.2,243,621 5/1941 Denoix ..l02/80 p J 2,493,278 1/1950 Weiss ..l02/7l X 4Claims, 2 Drawing Figures 2 1 11:, I sss l9 PATENTED JAMES I972 FIG. I

I NVENTOR. ROBERT L. ASKE ATTORNEY CONTROL APPARATUS BACKGROUND OFTHEINVENTION 1. Field of the Invention The present invention pertains tofuses for ordnance projectiles and, more particularly, stabilizedprojectile fuses having a velocity-responsive self-destruct feature.

2. Description of the Prior Art Self-destruct mechanisms to detonate acharge within a projectile if impact does not occur within apredetermined flight distance are common in the prior art. Popularmechanisms for efiecting self-destruct have employed spin decay inspin-stabilized projectiles to indicate the distance covered afterlaunch. Another commonly used indicator for flight distance is a simpletime delay. Time delay devices such as mechanical timers, gasgenerators, electronic timers, and pyrotechnic delay arrangements arecommonly used to initiate the explosive projectile after a predeterminedtime period in the absence of impact.

For small caliber projectiles with slow spin rates, the spin rate is aless satisfactory indication of distance covered and the point at whichself-destruct should be initiated. In a nonspinning or low-spinprojectile, spin decay is thus not a reliable indication of flightdistance.

Timing devices are necessarily complex to attain a reliable indicationof actual flight distance for self-destruct purposes. In addition,timers of the electronic variety require a source of power which is alsoundesirable in small caliber munitions.

It is an object of the present invention to provide an improvedself-destruct mechanism which is responsive to the velocity decay ofaprojectile.

SUMMARY OF THE INVENTION The present invention pertains to the use ofdynamic pressure on the nose of a moving projectile to indicate velocitydecay and initiate self-destruct of the projectile. The inventionprovides an entirely mechanical mechanism suitable for use with smallcaliber munitions.

A movable nose cap is slidably engaged in an opening in the nose of aprojectile where it is subject to dynamic pressure due to movement ofthe projectile through a fluid medium. Drag forces on the nose cap atarming overbalance a spring force from within the ogive tending to pushthe nose cap forward. As the velocity of the projectile decreases, dragpressures also decrease and the spring pressure exerted from within theogive overcomes the dynamic pressure pushing the nose cap forward andreleasing a striker to actuate a detonator.

The preferred embodiment of the invention utilizes a delay fuse forspinning projectiles of the type shown in US. Pa. No. 3,326,132, issuedto E. W. Tlam and assigned to the assignee of the present invention. TheTlam device provides delayed arming for a projectile subject to setbackforce upon launch, rotational force during flight, and impact force atthe termination of the flight. The projectile fuse shown has all thefeatures of the Tlam device with, in addition, the self-destructmechanism of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a fuse embodimentutilizing the self-destruct mechanism of the present invention.

FIG. 2 is an exploded view of the fuse of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring jointly to FIGS. 1 and2, an ogive 1 has a hollowed-out portion of cylindrical cross section ofvarying diameters and a cylindrical opening to the nose. The inner wallof the cylindrical opening defines a circular groove 7.

A nose cap 16, having a cylindrical center cavity and a tubular tailextension with four holes 17 through the walls of the extension in acircumferential pattern, is slideably engaged in the cylindrical noseopening of ogive 1. An annular seal 20 is positioned between the nosecap 16 and the ogive 1. Four detent balls 19 are disposed within thefour holes 17 holding a plunger 21 urged by a spring 22 within the nosecap. The nose cap is secured to the ogive by a setback weight 18 whichis press fitted onto the tubular extension of nose cap 16 within theogive. A flange is formed on the end of the extension after the nose capis secured.

A cylindrical piston 12, having a one-way seal 13 around its periphery,a centrally positioned striker 11, and a porous restrictor 15 located inan axial port in the piston, is disposed within a cylindrical crosssection hollowed portion of ogive 1. The seal 13 is oriented to alloweasy movement of the striker toward the base of the projectile whilemovement in the other direction requires that displaced air travelthrough porous restrictor 15.

A cylindrical body assembly 4 holds a spring 14 against the base ofpiston 12 urging the striker 11 against the plunger 21. Contained withinthe body assembly 4 is a diametrically pivoted, cylindrical rotor 5carrying a stab detonator 8. The rotor 5 further has a detent 6 andcentrifugal weights 9a, 9b, and 9c. The rotor 5 is locked in a fixedposition relative to body member 4 by the end of striker 11.

A deformable setback washer 10 is held against the end of body member 4by a base 2 containing a lead assembly 3. The base 2 has an opening totransfer detonation of the lead assembly to the main charge (not shown)in proximity to base 2.

Detent balls 19 retain the plunger 21 urged by spring 22 within nose cap16. The circular groove 7 in the inner wall of the cylindrical openingis located slightly ahead of the detent ball location and is of suchsize to permit the balls 19 to move radially outward when the nose cap16 moves forward, thereby releasing plunger 21.

OPERATION With the exception of the self-destruct mechanism, operationofthe fuse is described in the Tlam patent 3,326,132.

Upon setback, the setback washer 10 collapses and setback weight 18slides rearward down the tubular extension of nose cap 16 until itcontacts the flanged end of the extended portion.

As the body member 4 compresses setback washer 10, piston assembly 12 iscarried rearward by the inertia of striker 11. The one-way seal 13 onpiston member 12 allows easy travel of the piston to the rear of theogive. After setback, the spring 14 urges the piston 12, carrying thestriker l1, forward with a time delay determined by the nature ofrestrictor 15. As the piston 12, carrying striker 11, moves toward thenose of the ogive due to the pressure exerted by spring 14, the airdisplaced ahead of the piston 12 must pass through the port in thepiston 12. The time delay is controlled by the port size and therestrictor 15 material. As the piston 12 carries the striker 11 forward,the rotor 5 within body member 4 is released and, due to spinning of theprojectile, is rotated into an armed position with the stab detonator inline with the striker and an output hole in the bottom of body member 4.A cylindrical detent 6 locks the rotor in the armed position.

The fuse is now in the armed position. Three functioning actions are nowpossible:

1. Hard target impactcollapse of the nose cap and ogive drives thestriker 11 aft into the stab detonator 8 providing a super quickfunction.

2. Graze or soft targetinertia action drives the body assembly 4 forwardwhere the stab detonator impacts the firing pin 11 providing an inertia"function.

3. Self-destruct-after a flight of predetermined length without impactas determine by the mechanism design, piston spring 14 drives the pistonassembly 12 and the nose cap 16 against the dynamic pressure exerted onthe nose cap. The nose cap slides forward causing the four ball detents19 to release the spring-loaded plunger 21, thus forcing striker l1engaged in piston 12 into stab detonator 8 and providing a self-destructfunction.

An analysis of the preferred embodiment of the invention shown in FIGS.1 and 2 illustrates the design considerations for triggering of theself-destruct mechanism. The nose cap 16 will be pushed forward by thespring 14 when the force of spring 14 exceeds the combined friction anddynamic drag force acting on the nose cap and plunger. The dynamic dragforce acts on the nose cap with a force dependent on projectilevelocity, drag coefficient, drag reference area, and the medium density.The frictional force is dependent on the number of balls, the staticfriction coefficient between the balls and the inner wall of thecylindrical passageway in ogive l, and the forces acting on each balldetent normal to the axis of the projectile.

Many modifications and embodiments are possible within the scope andspirit of the present invention. I wish to be limited only by theappended claims wherein I claim:

1. An improved self-destruct mechanism for use with a flight-stabilizedprojectile having a detonator disposed within an ogive, wherein theimprovement comprises:

a nose cap slideably engaged within an opening in said ogive;

spring means, disposed within said ogive, for urging said nose cap awayfrom said ogive after launch;

spring-actuated striker means, disposed within said ogive for actuatingsaid detonator; and

detent means for retaining and releasing said spring actuated strikermeans upon movement of said nose cap away from said ogive,

whereby dynamic forces against said nose cap, dependent on projectilevelocity, decrease and said spring means moves said nose cap away fromsaid ogive causing said projectile to self-destruct after traveling apredetermined distance.

2, The improved self-destruct mechanism of claim 1 wherein:

said nose cap is a tubular member having a closed forward end with acircumferential pattern of holes in the rearward extension thereof;

said spring-actuated striker means comprises:

a striker means member having a pointed end in juxtaposition with saiddetonator,

a cylindrical plunger member lying within said nose cap and having aflangular extension on the end thereof distal proximate said closedforward end of said nose cap, said plunger further in line with saidstriker member, and

a helical spring surrounding said plunger member positioned between saidflangular extension and said closed forward end; and

said detent means comprises a plurality of ball members disposed withinsaid holes in said rearward extension of said nose cap acting againstsaid flangular extension of said plunger holding said helical springcompressed, said detent means further including a circumferential groovein the inner wall of said opening in said ogive in a location forward ofthe position of said ball members disposed within said holes when saidnose cap is fully engaged in said opening, whereby said ball members areforced outwardly into said groove upon movement of said nose capforward, thereby releasing said plunger member, forcing said strikermember into said detonator causing selfdestruct.

3. A fuse for a spinning projectile subject to decreasing velocity afterlaunch due to drag forces acting on said projectile comprising delayedarming impact means having a firing pin and a detonator for delayedarming and for firing ofa munition subject of setback, spin, and impact,in combination with velocity-responsive apparatus of claim 3 havingmovable means for receiving a drag force dependent on relative velocitywith respect to a fluid medium, spring means for acting on said movablemeans in opposition to said drag force and actuator means operativelyconnected to said firing pin, for providing a mechanical output inresponse to movement of said movable means by said spring means inopposition to said drag force, whereby said mechanical output ires saiddetonator after the velocity of said projectile drops to a predeterminedlevel.

4. An improved velocity-dependent self-destruct mechanism for use with aflight-stabilized projectile having a detonator disposed within anogive, wherein the improvement comprises:

a nose cap slideably engaged within an opening in said ogive;

spring-actuated striker means disposed within said ogive for actuatingsaid detonator;

spring means disposed within said ogive for urging said nose cap awayfrom said ogive after launch, said urging being opposed by dynamicforces against said nose cap, said dynamic forces being dependent onprojectile velocity; and

detent means for retaining said spring-actuated striker means until theforce due to said spring means sufficiently overcomes the dynamic forcedue to projectile velocity and said spring means causes said nose cap tomove a predetermined distance away from said ogive causing said detentmeans to release said spring-actuated striker means, thereby allowingsaid striker means to initiate said detonator.

1. An improved self-destruct mechanism for use with a flightstabilizedprojectile having a detonator disposed within an ogive, wherein theimprovement comprises: a nose cap slidably engaged within an opening insaid ogive; spring means, disposed within said ogive, for urging saidnose cap away from said ogive after launch; spring-actuated strikermeans, disposed within said ogive for actuating said detonator; anddetent means for retaining and releasing said spring actuated strikermeans upon movement of said nose cap away from said ogive, wherebydynamic forces against said nose cap, dependent on projectile velocity,decrease and said spring means moves said nose cap away from said ogivecausing said projectile to selfdestruct after traveling a predetermineddistance.
 2. The improved self-destruct mechanism of claim 1 wherein:said nose cap is a tubular member having a closed forward end with acircumferential pattern of holes in the rearward extension thereof; saidspring-actuated striker means comprises: a striker member having apointed end in juxtaposition with said detonator, a cylindrical plungermember lying within said nose cap and having a flangular extension onthe end thereof distal proximate said closed forward end of said nosecap, said plunger further in line with said striker member, and ahelical spring surrounding said plunger member positioned between saidflangular extension and said closed forward end; and said detent meanscomprises a plurality of ball members disposed within said holes in saidrearward extension of said nose cap acting against said flangularextension of said plunger holding said helical spring compressed, saiddetent means further including a circumferential groove in the innerwall of said opening in said ogive in a location forward of the positionof said ball members disposed within said holes when said nose cap isfully engaged in said opening, whereby said ball members are forcedoutwardly into said groove upon movement of said nose cap forward,thereby releasing said plunger member, forcing said striker member intosaid detonator causing self-destruct.
 3. A fuse for a spinningprojectile subject to decreasing velocity after launch due to dragforces acting on said projectile comprising delayed arming impact meanshaving a firing pin and a detonator for delayed arming and for firing ofa munition subject of setback, spin, and impact, in combination withvelocity-responsive apparatus of claim 3 having movable means forreceiving a drag force dependent on relative velocity with respect to afluid medium, spring means for acting on said movable means inopposition to said drag force and actuator means operatively connectedto said firing pin, for providing a mechanical output in response tomovement of said movable means by said spring means in opposition tosaid drag force, whereby said mechanical output fires said detonatorafter the velocity of said projectile drops to a predetermined level. 4.An improved velocity-dependent self-destruct mechanism for use with aflight-stabilized projectile having a detonator disposed within anogive, wherein the improvement comprises: a nose cap slidably engagedwithin an opening in said ogive; spring-actuated striker means disposedwithin said ogive for actuating said detonator; spring means disposedwithin said ogive for urging said nose cap away from said ogive afterlaunch, said urging being opposed by dynamic forces against said nosecap, said dynamic forces being dependent on projectile velocity; anddetent means for retaining said spring-actuated striker means until theforce due to said spring means sufficiently overcomes the dynamic forcedue to projectile velocity and said spring means causes said nose cap tomove a predetermined distance away from said ogive causing said detentmeans to release said spring-actuated striker means, thereby allowingsaid striker means to initiate said detonator.